How it works
How UMBR compares
Where UMBR sits next to public transfers, custodial accounts, mixers and other privacy systems, including where it falls short.
Two different jobs#
"Private crypto" covers two jobs that are easy to blur. Payments privacy means a salary, an invoice or a balance is not readable by everyone. Trading privacy means your orders and positions do not leak to the market before or after you act.
UMBR is built for the first job. Private balances, private sends, payroll and proofs work on testnets today. Trading from a private balance is the harder problem, because a trade has to meet liquidity somewhere. Our sealed trade path exists but is switched off until it can be done without leaking.
Who holds the key#
With a custodial service, the company holds your funds and your records. Privacy means trusting it not to look, not to leak and not to be compelled. With UMBR, the keys that spend your notes and read your history are generated and kept on your device. The pool contract enforces the rules; no UMBR server can move your money or read your balance.
The trade-off is responsibility. There is no password reset. If you lose your keys without a backup, nobody can recover them for you.
What a breach exposes#
A custodial database leak can expose every customer at once: names, balances, transfers. UMBR has no such database of balances to leak. The chain stores commitments and encrypted notes that are useless without keys. A breach of the UMBR website or relayer would expose IP addresses and timing, and a compromised frontend could attack users who load it, which is why the threat model treats the frontend as part of the trust base. A compromised user device exposes that user only.
Not new cryptography#
UMBR stands on years of public research and open-source work. The note, commitment and nullifier model comes from the Zcash family of designs. Proofs use Groth16, a widely deployed succinct proof system. Hashing inside circuits uses Poseidon, which was designed for exactly this setting. We credit that lineage plainly: our job is to apply it carefully to stablecoin payments and to build usable products on top, not to invent new primitives.
Side by side#
These are broad categories, not specific products. Individual services vary.
| Question | Public stablecoin transfer | Custodial account or exchange | Mixer-style pool | UMBR |
|---|---|---|---|---|
| Who holds the funds | You | The provider | You, via the pool contract | You, via the pool contract |
| Amounts on the public record | Yes | No, but the provider sees all | Usually fixed denominations | Hidden inside the pool |
| Sender to receiver link | Public | Known to the provider | Hidden inside the pool | Hidden inside the pool |
| Pay someone inside the system | Yes | Yes, if they have an account | Usually no; deposit and withdraw only | Yes, to an UMBR address or link |
| Prove one fact to an auditor | Everything is already public | Provider statements | Rarely supported | Scoped proofs with audience and expiry |
| A breach exposes | Nothing new; it is public | Every customer's records | Your own device only | Your own device only |
| Payroll | Public salary sheet | Supported, provider sees it | Not designed for it | Private run, provable total |
Where UMBR is behind#
- Maturity. UMBR runs on testnets and has not been externally audited. Older shielded systems have years of production use.
- Anonymity set. Young pools are small. Established systems give far more cover today.
- Trading. Sealed trade is switched off. Private swaps are not available.
- Recovery. A custodial account can reset your password. UMBR cannot.
- Convenience. Proofs take seconds on a laptop and longer on a phone, and transactions cost more gas than a plain transfer.
- Reach. Two chains, a few stablecoins. Nothing else yet.
The short version#
If you want stablecoin payments and payroll that the public cannot read, keys you hold yourself and a way to prove one fact to an auditor, UMBR is built for that, on testnet today. If you need a large anonymity set, audited production code or private trading right now, it is not there yet.
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